Magnetic recording disk drive with write current overshoot amplitude (OSA) responsive to data transitions
US9111561B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2014 |
| Grant date | Aug 18, 2015 |
| Priority date | — |
| Expiry date | Oct 28, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10018
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A disk drive dynamic wave shaper (DWS) write driver includes a write current generator that produces a baseline output current for the write current pulses and an overshoot current generator that produces an overshoot current with different values. The overshoot current is added to the baseline current, with the value of the overshoot current amplitude (OSA) being selected in response to the frequency of transitions in the write data signal. The write driver includes logic circuitry that detects the pattern of transitions. Transitions that are immediately followed by a transition will receive a larger-than-nominal OSA1, transitions that are not immediately followed by a transition and that are not preceded by a long sequence of non-transitions will receive a nominal OSA2, and transitions after longer sequences of non-transitions will receive a smaller-than-nominal OSA3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.